ADORA2A and Parkinson disease: With the approval of the A2AR antagonist istradefylline [60] for treating PD patients by the FDA, the ability of A2AR antagonists, which not only enhanced gross motor activity but also improved cognition, led us to propose that A2AR antagonists may represent a novel therapeutic target for reversing fine movement deficits in PD patients (with the finger tapping or finger-to-thumb tapping test).